WO1998019942A1 - Transfer device - Google Patents

Abstract

The invention concerns a device for transferring bodies (9) supported by plates (Ai, Bi) following in succession in a mobile curved line; the plates are grouped in successive pairs (Ai, Bi) joined by a horizontal shaft (13) enabling their mutual rotation; the adjacent plates of two successive pairs (Bi-1, Ai; Bi, Ai+1) are coupled and articulated about at least one vertical rotation axis (2); further the horizontal shaft (13) is preferably arranged such that there is a clearance between the plates (Ai, Bi) so that they can slope with respect to each other perpendicularly to said horizontal and vertical axes.

Description

Transfer device.

The present invention relates to improvements made to body transfer devices, this device comprising a multiplicity of support plates for the respective bodies which are coupled one after the other in a movable curvilinear endless chain with joints capable of allowing the curvilinearity of said movable chain as well as simultaneously the rotation of the plates around a horizontal axis to overturn or straighten the bodies.

The improvements according to the invention preferably relate, although not exclusively, to devices for transferring hollow bodies of thermoplastic material provided with a neck opening such as preforms, bottles, flasks or the like, this device comprising a multiplicity of plates for supporting the respective hollow bodies which are coupled one after the other in a movable curvilinear endless chain with articulations capable of allowing the curvilinearity of said movable chain as well as simultaneously the rotation of the plates around a horizontal axis to reverse (neck at the bottom) or straighten (neck at the top) the hollow bodies.

A transfer chain constituted as mentioned above is encountered in particular in installations for manufacturing containers of thermoplastic material, such as bottles, flasks or the like, in particular for moving the preforms from a loading station to and through a heating oven (tunnel oven) in which the material constituting the preforms is heated and then molded, by a blowing or stretch-blowing process, into a large container (intermediate container or final container). The transfer chain is generally arranged so that the linear displacement of the preforms is accompanied, in addition to the above inversion / straightening, of a rotation of the preforms on themselves so that the material is heated uniformly over all around the preforms, the heating means being arranged unilaterally in the oven.

In known transfer devices, the successive stages are joined in an articulated manner to each other by means of spherical couplings, as described for example in the document FR

2,728,547 in the name of the Claimant.

This type of connection by spherical coupling offers the advantage of providing each plate with all the degrees of freedom of rotation desirable with respect to the framing plates, allowing the curvilinearity of the transfer chain, the straightening and reversal of the hollow bodies and the possibility for the chain to have a certain vertical deflection due to its weight. However, this known arrangement presents

1 disadvantage of being expensive to manufacture (sphere or spherical cap; spherical bowl).

In view of the large number of plates involved in the constitution of such a transfer chain (up to several hundred), it seemed desirable to design a transfer device capable of offering the same functional characteristics, but only involving simple joints, easy to manufacture and assemble, and therefore less expensive. For these purposes, a transfer device as mentioned in the preamble is characterized, being arranged in accordance with the invention, in that the body support plates are coupled as follows:

the plates are joined in successive pairs and the two plates of each pair are coupled by a horizontal shaft allowing the mutual rotation of the two plates around said shaft for the overturning or straightening of the bodies and,

- each of the two above-mentioned plates of a pair is coupled to another immediately adjacent plate belonging to a neighboring pair in an articulated fashion around at least one vertical axis of rotation which is suitable for authorizing their mutual inclination around said vertical axis.

Thanks to this arrangement, each axis of rotation (vertical allowing the curvilinearity of the chain; horizontal for the overturning / straightening of the hollow bodies) is constituted in a separate manner and therefore mechanically simple and of inexpensive design.

In a preferred embodiment, the aforesaid horizontal shaft coupling the two aforementioned plates of each pair is shaped so that a clearance remains between said two plates of each pair and so that these can tilt 1 'relative to 1 the other vertically by mutual rotation around an imaginary axis perpendicular to the above horizontal and vertical axes. Thus, not only we realize the two types of axis of rotation which are functionally required for a correct treatment of the transported bodies, but in addition we give to the system a third degree of freedom in rotation which, although being of angular amplitude very limited at each coupling shaft, is however sufficient to avoid jamming of the plates against each other under the action of their own weight (arrow). Advantageously, the shaft prohibits the mutual inclination of these two plates (A ^ B ^ about a vertical axis; it is also advantageous that the coupling of two plates belonging rexpectively to neighboring pairs is suitable for prohibiting their mutual rotation around a horizontal axis.

In a preferred embodiment due to its structural simplicity and its relatively low cost, the horizontal coupling shaft of the two plates is rigidly secured, by one of its ends, to a first of the plates and is connected to the second plate, by its other end, by means of a bearing with balls; preferably then, the ball bearing comprises, on the one hand, an inner cage surrounding said other end of the coupling shaft and pressing against an end bearing formed by an enlarged head from said end of the shaft and, on the other hand, an outer cage retained in a cavity provided in said second plate; it is then desirable that the aforementioned clearance between the two plates of the same pair is authorized thanks to the conformation of the inner cage, the outer cage and the balls.

As for the articulation of the plates around vertical axes suitable for authorizing a curvilinear trajectory of the transfer chain, it is desirable to provide a coupling piece interposed between each of the above two plates and the plate which is immediately adjacent, said coupling piece being articulated with the two plates which it then joins around two respective axes of rotation; preferably then, the two axes of rotation of the coupling piece and of the two respective plates are respectively coaxial with the bodies supported by the plates. Thanks to this arrangement, all the bodies coincide with vertical axes of rotation of the support plates and it is thus ensured that all the bodies follow strictly identical trajectories in the curved portions of movement of the chain, which is extremely important for example when it comes to bodies which pass in front of heating lamps during a heat treatment.

It is therefore interesting to take advantage of the presence of the coupling part to assign it additional functions. In particular, it is possible to ensure that the coupling piece further supports at least one guide member capable of cooperating with a fixed cam for controlling rotation around the above horizontal shaft for overturning or straightening the bodies. In this way, the two plates to which the coupling piece is coupled are driven in rotation in a perfectly synchronous manner and these two plates, although arranged head to tail, can be produced structurally in a strictly identical manner, which simplifies manufacture and reduces production costs.

By considering the arrangements in accordance with the invention which have just been exposed, it can be seen that the plates are no longer completely independent of one another, from the point of view of the various rotations, as was the case in the prior devices. The plates are, here, secured in the form of pairs: each plate is secured to one of the adjacent plates for rotation around the horizontal axis (reversal / straightening of the hollow bodies) and to the adjacent opposite plate for rotation around the vertical axis (curvilinearity of the chain). However, this joining in pairs poses in practice no problem and therefore does not constitute a handicap.

The invention will be better understood on reading the following description of certain embodiments given only by way of purely illustrative examples. In this description, reference is made to the appended drawings in which:

- Figure 1 is a side view, in section, of a portion of a body transfer device arranged in accordance with a preferred embodiment of the invention;

- Figure 2 is a top view in section along the line II-II of Figure 1;

- Figures 3 and 4 are views on a greatly enlarged scale, in side view, of a part of the device of Figure 1, respectively in two different functional positions;

- Figures 5 and 6 illustrate, in top view, respectively two other embodiments of the device of Figures 1 and 2; and

- Figure 7 is a fragmentary view illustrating an alternative embodiment of part of the device of FIGS. 1 to 6.

In the detailed description which follows, consideration will be given to a device for transferring hollow bodies which seems to constitute an interesting and preferred application of the invention, it being understood however that the invention can be applied to devices for transferring all bodies .

Referring first to Figure 1, there is shown a part of a hollow body transfer device in particular of thermoplastic material provided with an opening forming a neck such as preforms, bottles, flasks, etc.

The transfer device comprises a multiplicity of successive pairs of support plates A _if B _ir these plates being suitable for supporting respective hollow bodies. These plates are coupled one after the other in a manner which will be explained later so as to constitute a movable curvilinear endless chain. Each plate A _if B _t supports a vertical tubular body 1 in which a rod 2 is supported for free rotation with generally the possibility of axial displacement.

Each rod 2 has an upper end 3 projecting beyond the tubular body 1 and on which is fixed, integral in rotation, a toothed wheel 4 suitable for meshing with a link chain such as a Galle chain (not shown) which is arranged fixed along the path followed by the transfer device: the meshing of the wheel 4 with the fixed link chain causes the rotation of the rod 2 on itself, for example with a view to an exhibition regularity of a hollow body to the radiation of a heating element arranged unilaterally.

At its lower end, the rod 2 has a shoulder 5 on which rests a return spring 6 pressing at its other end against an internal shoulder 7 of the tubular body. The lower end of the rod 2 also supports a gripping head 8 suitable for gripping a hollow body 9 (middle rod in FIG. 1) by its neck. In the example shown, the gripping head 8 has a central core 10 supporting a radially elastically deformable peripheral ring 11 which, being introduced into the neck of the hollow body 9, retains the latter by friction.

In FIG. 1, the two left and middle rods are maintained in the low position under the action of the return spring 6 (loaded position), while the right rod is raised under the action of an external force ( for example a cam) against the spring 6 so that the gripping head 8 rises in a tubular skirt 12 extending the tubular body 1 downwards and driving the hollow body 9 out of the gripping head 8 (unloaded position or waiting to load).

The arrangement which has just been described is given by way of example only and is not directly linked with the arrangements specific to the invention which will now be described more precisely.

As more easily visible in the three figures 2, 5 and 6, two consecutive plates h _t and B are coupled to each other by a horizontal shaft 13 (that is to say extending substantially in the direction movement of the endless chain) authorizing the only mutual rotation of the two plates A _ir B _i around said shaft (reversal of the hollow bodies neck at the bottom, or straightening of the hollow bodies neck at the top) and prohibiting any mutual sensitive inclination of these two plates around a vertical axis.

Furthermore, each of the two aforementioned h _ir B plates is coupled to another immediately adjacent plate (A _L with _L. Located to its left in the drawing; B _± with A _iti located to its right in the drawing) in an articulated fashion around of at least one vertical axis of rotation proper to only allow one mutual inclination of the plates A _{i + 1} and B _ir and A and B ^ around said vertical axis and to prohibit their mutual rotation about a horizontal axis.

As regards the latter arrangement, the corresponding overlapping ends can be coupled by a vertical pivot 14, pairs of plates A ^ B.,. _! , * B _L , A _{1 + 1} ; etc, as shown in Figure 5.

It is also possible, as illustrated in FIG. 6, to provide each plate A with an elongated part 15 (extending to the left in the drawing) suitable for partially overlapping plate B ₁ . ₁ adjacent and surrounding the tubular body 1 supported by the latter: thus it is said tubular bodies 1 of the plates B _t which constitute the pivots of vertical articulation. However, it will be noted that, both in the embodiment of FIG. 5 and in that of FIG. 6, at least some of the tubular bodies 1 do not strictly follow the median axis in the curved parts of the trajectory (the two tubular body 1 respectively of the plates A _t and B _t in the arrangement of FIG. 5; the tubular body 1 of the plate A _L in the arrangement of FIG. 6). In this case, at least certain tubular bodies are, in the curved parts of the trajectories, slightly offset towards the center of curvature. In certain applications, this can result in a serious drawback (for example when passing through a heating furnace, the hollow bodies supported by the rods 2 centered in these tubular bodies are substantially close together, respectively distant from the heating lamps arranged laterally depending on the mounting location of these lamps, and the heat treatment of these hollow bodies is incorrect).

To avoid this drawback, one can advantageously have recourse to the arrangement of FIG. 2 in which a coupling piece 16 has been used which is interposed between the plates to be coupled A _ir B _t _; B _if A _{1 + 1} ; etc. This coupling piece 16 is arranged to overlap partially the plates B and A _itl (or Aj and B ^), surrounding the tubular bodies 1 supported by them. In this way, the axes of all the tubular bodies 1 of the device coincide with vertical axes of articulation and it is then ensured that all the hollow bodies supported by said tubular bodies strictly follow the same centered trajectory.

One can take advantage of the space available on the coupling pieces 16 to equip them with certain accessories, for example the wheels or rollers 17, 18 necessary for the straightening / turning control by cooperation with a fixed cam.

As regards the coupling of the plates Ai, B _t via a horizontal shaft 13, it is advantageous to have recourse to the preferred embodiment illustrated in FIG. 1 and, on an enlarged scale, in FIGS. 3 and 4.

At one of its ends, the shaft 13 can be rigidly secured to one of the plates, here the plate A _(for this purpose, it can be provided that the plate A _t is provided with an axial housing 19 in which is engaged without significant play said end of the shaft 13 and a vertical pin 20 is fitted into coincidental holes made in the plate A _L and the shaft 13 to lock the shaft in the plate both axially and in rotation.

The other end of the shaft 13 is engaged in a cavity 21 inside the other plate B _j and a ball bearing 22 is interposed between the shaft 13 and the plate B ^ For this purpose, the internal cage 24 of the ball bearing surrounds the shaft 13 and bears axially against a bearing surface formed by an enlarged end head 23 of the shaft 13. The outer cage 26 of the ball bearing 22 rests against the wall of the aforementioned cavity 21 and is in axial support against a front edge of the cavity 21. The internal cage 24 has a peripheral annular edge 25 extending radially relative to the shaft 13, on the side of the enlarged end head 23, and in the direction of the outer cage 26. The outer cage 26 has a peripheral annular flange 27 extending radially relative to the shaft 13, side opposite to the enlarged head 23, and in the direction of the inner cage 24. Thus, in operation, the balls 28 are wedged between the cages 24, 26 not only radially, but also axially and transmit the tensile force of a platinum to the next when moving the chain.

Finally, the surfaces facing each other of the plates A _j and B respectively are substantially flat so as to facilitate the mutual rotational movement.

However, as can be seen in FIG. 3, it is desirable that the two surfaces facing each other of the plates A _A and B _t not be kept strictly pressed against each other and that the length of the shaft 13 is determined so that a sensitive play, although very weak, remains between them. In FIGS. 3 and 4, this game has been considerably enlarged to facilitate the reading of the drawings; but in practice a clearance e of less than about 0.8 mm, preferably of the order of 0.2 to 0.5 mm, may be sufficient for the most common architectures of the installations concerned. Due to this arrangement, the shaft 13 remains perfectly integral with the A _ir plate but, as illustrated in FIG. 4, the Bi plate can rotate or tilt relative to the A _ir plate thanks to the possibility of 'A slight mutual offset of the two cages 24, 26 of the ball bearing and within the limit imposed by the value of the clearance e. This displacement or tilting corresponds to a capacity for rotation about an imaginary axis of rotation perpendicular jointly to the horizontal (shaft 13) and vertical (axis of the tubular bodies 1) axes mentioned above.

This allows the entire chain to locally take the deflection required for correct operation of the device despite the heavy weight of each element (all parts are machined from steel). Of course, the coupling between the pairs of plates A _t and B _± could be carried out in different ways. In particular, it is not imperative that the shaft 13 is integral in rotation with one of the plates (here the plate A _t ), and it could just as easily be coupled to the plate A _t with free rotation, possibly with the interposition of a bearing. By way of example, in FIG. 7, the shaft 13 has a second enlarged head 29 which is engaged in a threaded recess 30 of the plate A and which is retained there and locked axially by a nut 31.

However, the embodiment which has been more specifically described above and represented in the drawings is that which currently seems the most suitable in terms of mechanical strength and reliability, structural simplicity and also cost. reduced as much as possible for both manufacturing and maintenance.

Claims

1. Body transfer device, this device comprising a multiplicity of plates (A _ir B _i ) for supporting the respective bodies which are coupled one after the other in a movable curvilinear endless chain with joints capable of authorizing the curvilinearity of said movable chain as well as simultaneously the rotation of the plates around a horizontal axis to overturn or straighten the bodies, characterized in that the body support plates are coupled as follows: - the plates are joined in pairs (A _ir B _t ) successive and the two plates (Ai, Bi) of each pair are coupled by a horizontal shaft (13) allowing the mutual rotation of the two plates around said shaft for overturning or body straightening (9), and - each of the two aforementioned plates (respectively A _ir B _t ) of a pair is coupled to another immediately adjacent plate belonging to a neighboring pair (respectively B ^; A _{i + 1} ) in an articulated fashion around the at least one vertical axis of rotation suitable for authorizing their mutual inclination around said vertical axis. 2. Device according to claim 1, characterized in that in addition, the aforesaid horizontal shaft (13) coupling the two above-mentioned plates (Ai, Bi) of a pair is shaped so that a clearance remains between said two plates (A _ir B _t ) of each pair and that the latter can tilt one with respect to the other vertically by mutual rotation around an imaginary axis perpendicular together with the above horizontal and vertical axes. 3. Device according to claim 1 or 2, characterized in that the horizontal shaft (13) coupling the two plates (A _ir B) of each pair of plates prohibits the mutual inclination of these two plates (Ai, Bi) around of a vertical axis. 4. Device according to any one of the claims. tions above, characterized in that the coupling of two plates belonging respectively to neighboring pairs is suitable for preventing their mutual rotation about a horizontal axis. 5. Device according to any one of the preceding claims, characterized in that the horizontal shaft (13) for coupling the two plates (A _ir B _t ) of a pair is rigidly secured, by one of its ends, d 'a first of the plates (A ^ and is connected to the second plate (Bi), by its other end, by means of a ball bearing (22). 6. Device according to claim 5, characterized in that the ball bearing (22) comprises, on the one hand, an inner cage surrounding said other end of the coupling shaft (13) and in abutment against an end bearing formed by an enlarged head (23) of said end of the shaft (13) and, on the other hand, an outer cage retained in a cavity (21) provided in said second plate (Bi). 7. Device according to claim 6, characterized in that the conformation of the inner cage (24), the outer cage (26) and the balls (28) allows the above play between the two plates (Ai, Bi) of the same pair. 8. Device according to any one of the preceding claims, characterized in that it comprises a coupling piece (16) interposed between each of the two above-mentioned plates (respectively Ai; B _t ) and the plate which is immediately attached to it adjacent (respectively B ^; A _{i + 1} ), said coupling piece (16) being articulated with the two plates which it joins (A _ir B _i , ₁ ; A _{1 + 1} , Bi) around two respective axes of rotation. 9. Device according to claim 8, characterized in that the two axes of rotation of the coupling piece (16) and the two respective plates are respectively coaxial with the tubular bodies (1) supported by the plates. 10. Device according to claim 8 or 9, characterized in that the coupling piece (16) further supports at least one guide member (17, 18) adapted to cooperate with a fixed cam for controlling rotation around the above horizontal shaft for overturning or straightening bodies. 11. Device for transferring hollow bodies (9) made of plastic material provided with an opening forming a neck such as preforms, bottles, flasks or the like, this device comprising a multiplicity of plates (A _ir B) for supporting the hollow bodies respective which are coupled one after the other in a movable curvilinear endless chain with articulations capable of allowing the curvilinearity of said movable chain as well as simultaneously the rotation of the plates around a horizontal axis to overturn (neck in bottom) or straighten (neck at the top) the hollow bodies, characterized in that it is constituted according to any one of the preceding claims.